1. Field
This disclosure relates to expansion modules used in computing systems, more particularly to techniques to manage modules configurations.
2. Background
Typical computer systems, such as personal computers, have moved to a more modular architecture, with components that can be easily added and removed. In many instances, these components are on modules, relatively small printed circuit boards with a connector on one end. Alternatively, they may be wired directly into the main system board or ‘motherboard.’ These modules, whether insertable or wired, will be referred to here as expansion modules. The connector allows the module to be ‘plugged in’ to the main processor board along a communication bus that allows the component on the module to communicate with the main processor, or wired to the board.
Typically, a defined protocol is used to handle communications between the central processing unit and the expansion module, such as the peripheral component interface (PCI) protocol. The PCI protocol describes the framework used to manage these communications and the bus traffic, although other types of protocols are available. Any type of system expansion bus may have expansion modules.
Using the example of PCI modules, systems can be expanded to include multiple communication capabilities, such as modems and local area network modules. Peripheral devices such as printers and scanners, expansion memory and many other types of components can reside on these modules, providing a user with a system with many different possibilities. However, the main processor or central processing unit (CPU) has to manage all of the communications between these various modules.
For example, each PCI module typically has firmware running on its controller or processor that handles requests from the CPU. When the request is complete, the PCI module signals the CPU with an interrupt. This can have a negative impact on the processing speed of the system, as well as the processing efficiency. The CPU must process the interrupt, slowing its processing on other tasks. Similarly, it increases the number of processing cycles required to complete tasks, as some of the cycles are consumer answering and then canceling the interrupts from the PCI modules.
Therefore, it would seem useful if some sort of configuration were available that allowed an expansion module to act as the master or main module for a subset of other modules. This configuration would be more useful if it were also adaptable to different types of expansion modules, beyond those using PCI protocols.